Air conditioning apparatus



H. GEBSON AIR CONDITIONING APPARATUS Nov. 12, 1940.

Filed Nov. 18, 41939 Inventor: H al Gi been,

lay-H CLOSED QJMZW, H is zzcor ney Patented Nov. 12, 1940 AIR. CONDITIONING APPARATUS Hal Gibson, Dallas, Ten, assignor to General Electric Company, a corporation of New York Application November 18, 1939, Serial N 0. 305,135

. 4 Claims.

My invention relates to air conditioning apparatus, and particularly to reversed cycle refrigerating machines employed for heating.

Reversed cyclerefrigerating machines, or heat pumps are sometimes employed in air condition-' ing systems for heating and may be arranged to transfer heat to the conditioned air from a suitable body of water or from the outdoor air. During the heating season there is a wide range of temperature of the outdoor air and heat pumps utilizing the outdoor air as a source of heat must be designed to supply the heating load under severe weather conditions. During mild weather in the heating season, the heat pump capacity is large as compared with the load requirements, and it is, therefore, desirable to provide some arrangement for varying the effective capacityof the refrigerating machine under different outdoor temperature conditions.

It is an object of my invention to provide a refrigerating system utilizing a plurality of refrigerating machines and including an improved arrangement for adjusting the capacity of the machines under varying conditions of load.

Another object of my invention is to provide an air conditioning system employing a plurality of refrigeratiu machines and an improved arrangement for interconnecting portions of the refrigerant circuits of the machines in order to vary the capacity of the machines under different load conditions;

Further objects and advantages of my invention will become apparent as the following description proceeds, and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

For a better understanding of my invention, reference may be had to the accompanying drawing, the single figure of which. shows diagrammatically an air conditioning system embodying my invention.

In order to provide different effective capacities of-a heat pump, I provide two or more refrigerating machines and arrange the condensers or indoor heatexchangers of two or more of the Referring now to the drawing, I have illustrated an air conditioning system including a duct or casing l0 provided with a room. air inlet H, a fresh air inlet i2, and a discharge duct or conditioned air outlet l3. Within the duct I provide 5 a filter I1 and a temperature changing unit l4 .comprising heat exchange elements I5 and I6. During the operation of the conditioning system, return air and fresh air are admitted to the casing l0 through the inlets II and 2 respectively, 19 by operation of a fan I8 driven by a motor l9. The air passes through the filter I1 and over the surface of the heat exchange unit l4 and is conducted to the enclosure through discharge duct I3. In order to supply heating or cooling fluid to the unit I4, I provide two reversible refrigeratingmachines 20 and 2| connected to supply refrigerant to the heat exchange elements l5 and I6, respectively. The refrigerating machine 20 comprises a compressor 22 driven by a motor 23 and connected in a refrigerant circuit including a heat exchange element 24 arranged in an air .duct 25, and the heat exchange element |5' in the casing l0. Outdoor air is circulated through the duct 25 by a fan 25a driven by a motor 25b. 25 The refrigerating machine 2| comprises a compressor 26 driven by a motor 21 and connected in a refrigerant circuit including a heat exchange element 28 arranged in the air duct 25 and the heat exchange element H5 in the casing in. 80

In the drawing, the refrigerating machines 2, and 2| have been illustrated with their circuits arranged so that hot compressed refrigerant supplied to the elements l5 and I6, heat absorbed 85 from the outdoor air by the elements 24 and 22 acting as evaporators being transferred to the air in the casing H1. The compressor 22- is arranged to supply hot compressed refrigerant from a discharge outlet 29 through an open valve 30 and conduit 3| to the heat exchange element l5 which acts as a condenser. The condensed refrigerant flowing from the element |5 through a normally open valve 32 and a check valve 33 which bypasses a thermostatic expansion valve 34 and thence to a liquid receiver 35. The liquid receiver 35 is connected to supply liquid refrigerant to the heat exchange element 24 through a check valve 36, scale trap 31 and thermostatic expansion valve 38, the valve 38 having a thermal element 39 on the outlet side of the element 24. Liquid refrigerant vaporized in the heat exchange element 24 returns to the compressor through a conduit 40, an open valve 4|, and a suction connection 42 to the condenser 22. When it is desired to reverse the operation of the refrigerating machine 20 in order to cool the air passing through the casing ID, the valves 30 and 4| are closed and valves 43 and 44 are opened. Compressor 22 then discharges hot compressed refrigerant through the valve 43 and conduit to the heat exchange element 24 where the refrigerant is condensed by the cooling action of the air passing through the duct 25. The condensed refrigerant passes through a check valve 45, bypassing the check valve 36 and thermostatic expansion valve 38 and flows to the receiver 35. From the receiver 35, the liquid refrigerant passes through-a check valve 46 and scale trap 46a and thence to the heat exchange element I5 under the control of thermostatic expansion valve 34 which is provided with a thermal element 41 on the suction side of the element I5.

The refrigerating machine 2| is provided with connections and valves corresponding to and operating in the same manner as those in the refrigerating machine 20. During the heating operation, the compressor 26 is arranged to supply compressed refrigerant'from a discharge connection 48 through an open valve 49 and conduit 50 to the heat exchange element I6 where it is liquefied and flows through a check valve 5| bypassing a thermostatic valve 52 and a scale trap 52a, and collects in a liquid receiver 53. From the liquid receiver the refrigerant flows through a check valve 54 and a scale trap 54a and into the heat exchange element 28 under the control of a thermostatic expansion valve 55 having a thermal element 56 at the outlet side of the element 28. The refrigerant vaporized in the element 28 by the absorption of heat from air passing through the duct 25 is returned to the compressor through a conduit 57, an open valve 58, and a suction connection 59. When the refrigerating machine 2| is to be reversed, the valves 49 and 58 are closed and valves 68 and 6| are opened. The hot compressed refrigerant is then admitted to the heat exchange element 28 when it is cooled and liquefied and the liquid fiows therefrom through a check valve 62 by-passing the thermostatic valve 55 to the receiver 53. Refrigerant flowing from the receiver is admitted to the heat exchange element I6 under control of the thermostatic valve 52 having a thermal element 63 on the suc- 7 tion side of the heat exchange element I6, the

check valve 5| being closed and a check valve 64 opening to direct the refrigerant through the valve 52.

The refrigerating machines 26 and 2| are operated in'accordance with the temperature of the enclosure to be conditioned. For this purpose, I provide a thermostatic control 65 having a heating control element 66 and a cooling control element 61, a manual switch 68 being provided to select the cooling or heating control elements. The thermostatic control is energized by a transformer 69 having a primary coil connected across power supply line I3 and when there is a demand for heating the element 66 engages its left hand contact and closes a circuit through the secondary coil of the transformer and a coil 10 of a relay II. The relay is thereby operated, the lowermost arm closing a holding circuit therefor, and the upper pair of arms connecting motor lines I2 across power supply lines I3. The motors I9, 23, 25b and 21 'are thereby energized and actuate the refrigerating machines 26 and 2| and the air circulating fans I8 and 25a.

Under mild weather conditions, the heating 1 load is necessarily smaller while the air circusystem is thereby reducedand the refrigerating I machine 2| is employed to supply the entire heat exchange unit I4 with a heating medium at a lower mean temperature. In Order to connect the heat exchange element I5 in the refrigerant circuit of the refrigerating machine 2|, I provide connections or conduits I4 and I5 arranged to place the heat exchange element I5 in parallel across the heat exchange element I6. I also provide normally closed solenoid operated valves I6 and II in the conduits I4 and 15 respectively, and a thermostatic control I8 having a thermal element I9 responsive to the temperature of the outdoor air admitted to the conditioner through the duct I2.

The thermostatic control I8 includes a transformer connected to the power supply lines I3 through lines 86. In mild weather, when the temperature of the outdoor air rises to a predetermined value indicating that less than the entire capacity of the system is required, the thermal element I9 engages its left hand contact and thereby connects a coil 8| of the relay 82 across the secondary 83 of the transformer. The top arm of the relay closes 'a holding circuit for the coil 8|. The bottom arm opens the circuit of the motor 23 and then, together with the middle arm, closes a circuit from the lines 80 to solenoid coils 84 and 85 of the valves I6 and TI respectively. Operation of the refrigerating machine 20 is thereby stopped and the valves 16 and I1 opened to connect the heat exchange elements I5 and I6 in parallel in the circuit of the refrigerating machine 2|. Valves 43 and 44 and the valves of the compressor 22 effectively prevent the withdrawal of refrigerant from the machine 26 through the conduit 3| and the valve 32 is provided with a solenoid coil 86 connected across the coil 84- and energized therewith so that the valve 32 is closed to prevent the withdrawal of refrigerant from the machine 2| through the thermostatic expansion valve 34. When the heat exchange elements I5 and I6 are thus connected together they are bothavailable as condensing surface for the refrigerating machine 2| and all the air passing through the duct I0 is heated by a single refrigerating machine. The increase in the condenser surface of the machine 2| results in a reduced mean temperature of the condensing coils I5 and I6.

Whenever the temperature within the enclosure to be conditioned rises to the desired value, the element 66 of the thermostat moves to the right to engage its right hand contact and .shunts the coil 16 thereby causing it to drop out and open the switch II to deenergize the motors of the system and stop the heating operation.

Whenever theweather becomescolder and the full capacity of the system is required, the element IQ of the thermostatic control I8 moves to the left to engage its left hand contact thereby shunting the coil 8| and causing the switch 82 to drop out. By this operation the motor 23 is connected in the power circuit and the solenoids 84, 85 and 86 are deenergized to return the valves I6 and TI to their closed positions and the valve 32 to its open position.

aasnose the thermal element 6? in the relay circuit". A

manual switch 8!- in the line 80 may be opened so that the thermostatic control is will not operate to discontinue operation of the machine 28.

The operation of'the thermostatic control 65 during cooling effects energization of'the motors I9, 23, b and 21 in the same manner as the element 66 during the heating period. The element 67 on a demand for cooling engages its left hand contact to energize the coil 70 and when the cooling demand has been satisfied, it moves to the right to engage its right hand contact and deenergize the coil Ill.

From the foregoing, it will be seen that I have provided an arrangement for controlling eflectively the operation of a phirality of refrigerating machines to supply heat to an enclosure in such a manner that one of the machines may be removed from operation and the condensing cur-=- face of another machine increased to provide a lower mean temperature thereof and thereby re duce the heating capacity of the system.

While I have shown my invention in connection with an air conditioning system, other applicationswill readily be apparent to those skilled in the art. I do not, therefore, desire nw invention to be limitedto the particular construction shown and described, and I intend in the appendw claims to cover all modifications within the spirit and scope of my invention.

What I claim as new and desire to secure 1w Letters Patent of the United States is:

1. A refrigerating system comprising two refrlgerating machines, each of said machinesincluding a compressor and a condenser and an evaporator, means for connecting the condensers of both of said machines in the refrigerant circuit of one of said machines, means for energizing both of said machines, and means dependent upon a predetermined condition of load on said machines for actuating said connecting means to connect both of said condensers in the refrigerant circuit of said one of said machines and for deenergizing the other of said machines.

2. A refrigerating system comprising two re= frigerating machines, each of said machines in eluding a compressor anda condenser and an evaporator, means for conn the comic of both of said machines in the refrigerant cir-. cuit of one of said machines, means for energizing both of said machines, means dependent upon a predetermined condition of load on said machines for actuating said connecting means to connect both of said condensers in the refrigerant circuit of said one of said machines and for deenergizing the other of said machines, and

means for preventing the transfer of refrigerant from said other machine to said one machine when both of said condensers are connected to said one machine.

3. A system for conditioning the air within an enclosure including a duct, means for circulating air through said duct and into said enclosure, means including two refrigerating machines for changing the temperature of air circulated through said duct, each of said machinescomprising two heat exchange elements and a compressor for circulating refrigerant through said elements, each of said refrigerating machines having one of its heat exchange elements arranged in said duct and the other arranged outside said duct and outside said enclosure, means for connecting in the refrigerant circuit of one of said machines both said heat exchange elements arranged in said duct, and means dependent upon a condition of the air admitted to said duct for actuating said connecting means to connect in the refrigerant circuit of saidone machine both of said heat exchange elementsarranged in said duct and for deenergizing the other of said machines.

4. A system for conditioning the air within an enclosure including a duct, means for circulating all through said duct and into said enclosure,

' means for admitting fresh air to said duct, means including two reversed cycle refrigerating machines for heating air circulated through said duct, each of said machines comprising a con".

denser and an evaporator and a compressor connected in a. refrigerant circuit, the condenser of each of said refrigerating machines being arranged in said duct and the evaporator of each of said machines being arranged outside said duct and outside said enclosure, means for transferring the condenser of one of said machines from the refrigerant circuit of said one machine-to the refrigerant circuit of the other of said machines, and means'dependent" upon the temperature of the fresh air admitted to said duct for actuating? said last-mentioned means to connect both said condensers in the refrigerant circuit of said other machine and for deenergizing said one of said machines. o

HAL GIBSON, 

